This is a general warning to those using Debian Squeeze, and Debian Sid.
Debian Etch and Debian Lenny users are NOT affected.
The IANA port allocated for ManageSieve is 4190/tcp, and the old port used
by timsieved and other managesieve software in many distros (2000/tcp) is
allocated for Cisco SCCP usage, according to the IANA registry[1].
Starting with the version 4.38 of the Debian "netbase" package, the "sieve"
service will be moved from port 2000 to port 4190 in the /etc/services file.
Any installs which used the "sieve" service name instead of a numeric port
number will switch to the new port number as soon as the services are
restarted/reloaded, and in some cases, immediately after /etc/services is
updated.
This will affect Cyrus IMAP. This may also affect other sieve-enabled
software such as DoveCot.
In order to avoid downtime problems, mail cluster administrators using
Debian are urged to verify their Cyrus (and probably also DoveCot) installs,
and take measures to avoid services moving from port 2000/tcp to port
4190/tcp by surprise in either servers or clients.
It is worth noting that:
1. /etc/services will only be automatically updated if you never made any
modifications to it. Otherwise, you will be presented with a prompt by ucf
or dpkg asking you about the changes.
2. You can edit /etc/services and change the sieve port back to 2000 if you
want (this is not recommended, though).
3. You can edit /etc/cyrus.conf and any other relevant config files for your
mail/webmail cluster (e.g. on the sieve web frontends) ahead of time to
force them all to a static port number.
4. You can configure cyrus master to listen on *both* ports (2000 and 4190)
at the same time, and thus avoid the problem entirely. This also allows for
a much more smooth migration from port 2000 to port 4190.
[1] http://www.iana.org/assignments/port-numbers
--
"One disk to rule them all, One disk to find them. One disk to bring
them all and in the darkness grind them. In the Land of Redmond
where the shadows lie." -- The Silicon Valley Tarot
Henrique Holschuh